Choosing The Right Deck Screw Size For Treated Lumber

When it comes to choosing the right deck screw for 1-1/2 pressure-treated lumber, there are a few important factors to consider. Firstly, it is crucial to select a screw that is specifically designed for use with pressure-treated lumber. This type of wood contains chemicals that can corrode ordinary screws, compromising the structure's integrity. Galvanized or stainless steel screws are often recommended for their superior corrosion resistance. The size and length of the screw are also key considerations, ensuring maximum hold and stability for your project. For a secure fit, it is recommended to match the wood dimensions with the screw specifications. In addition, pre-drilling holes can help minimize wood splitting and provide a cleaner finish. When choosing a deck screw, it is important to prioritize corrosion resistance, longevity, and stability to ensure the safety and durability of your outdoor construction.

Deck Board Thickness

The standard size for decking boards typically falls between 5.5 and 6 inches in width and 1 to 1.5 inches in thickness. These dimensions offer a balance of stability, aesthetics, and ease of installation. The most popular thickness for decking boards in North America is 5/4 inches, which is actually about 1 inch thick.

The ideal thickness of your deck boards will depend on the intended use of your deck, as well as the local climate. If your deck will be subject to heavy snow loads, large gatherings, or commercial use, thicker boards are recommended for superior strength and longevity. In areas with severe weather conditions, thicker boards can also provide the extra sturdiness needed to withstand heavy snowfall or extreme temperatures.

When selecting the perfect deck board thickness, it is important to consider both practical and aesthetic factors. Thicker boards tend to give a more robust and substantial look to your deck, which may be preferable if you're aiming for a solid and imposing appearance.

Additionally, the width of your decking boards is an important consideration. While the standard width is 5.5 inches, narrower and wider options are available. For example, 4-inch-wide boards are perfect for a more refined and classic look, while 8-inch boards make a bold statement and are ideal for larger decks.

It is also worth noting that the strength of your decking boards is influenced by the type of wood or composite material used. Soft trees such as pressure-treated pine and western red cedar are weaker, while hardwoods like Black Locust are extremely strong. Composite decking products, although popular, are extremely weak and require joists to be placed very close together.

Material of the Deck Boards

The material of the deck boards is an important consideration when planning a decking project. There are several options available, each with its own advantages and disadvantages. Here is a detailed guide to help you choose the best material for your deck boards.

Wood Decking:

Wood decking is a traditional and timeless option that remains a favourite among homeowners due to its natural beauty. However, wood decking requires regular maintenance to preserve its appearance and structural integrity. The type of wood you choose will depend on your budget, the desired look, and the level of maintenance you are willing to commit to. Here are some common options:

• Pressure-Treated Wood: This is the most affordable and widely used decking material. It is made from southern yellow pine infused with preservative chemicals to resist rot, decay, and insect infestation. Pressure-treated wood can last for about 15 years with proper care, but it requires regular maintenance and can splinter if not properly maintained. It is important to note that the chemicals used in pressure-treated wood can be harmful to both people and the environment. When working with this type of wood, always wear a mask to avoid inhaling the harsh chemicals.
• Tropical Hardwoods: Tropical hardwoods such as ipe, cumaru, and red balau are known for their exceptional durability and rich colours. These dense woods can last up to 25 years and are naturally resistant to insects and decay. However, they are expensive and may raise environmental concerns due to the sourcing of these woods from endangered tropical rainforests.
• Cedar and Redwood: These woods are popular for their natural beauty and resistance to rot and insects. They offer a rich, warm colour and are lightweight, making them easy to work with. However, they are softwoods, which can make scratches and dents more noticeable. Regular maintenance is required to maintain their appearance, including power washing, sanding, and refinishing approximately every three years.

Composite Decking:

Composite decking is a low-maintenance alternative to wood. It is made from a blend of recycled plastic and wood fibres, offering the look of wood without the same level of upkeep. Composite decking is resistant to rot, warping, and splintering, and it does not need to be stained or sealed. It has a long lifespan of 25 years or more with proper care. Additionally, it is available in a wide range of colours and textures. However, composite decking is more expensive than regular wood, and it is heavier. There are two main types of composite decking:

• Uncapped Composite: This is the original form of composite decking, which is prone to staining and fading.
• Capped Composite: This type features a protective plastic shell that provides improved stain and fade resistance.

Plastic and PVC Decking:

Plastic and PVC decking materials offer excellent durability and low maintenance requirements. They are designed to resist fading, staining, and mould growth, making them a good choice for a long-lasting and low-upkeep decking solution. However, they don't always have the natural look and feel of wood, which may be unappealing to some. PVC decking is available in a range of qualities, but almost all options are highly resilient. Cellular PVC decking, in particular, offers exceptional durability and resistance to moisture, insects, and UV rays. It can last a lifetime with minimal maintenance.

Aluminum Decking:

Aluminum decking is an unconventional but worthwhile option. It is lightweight, strong, and resistant to mold, weather, insects, and even fire. It is also recyclable, making it a good choice for environmentally conscious buyers. However, aluminum decking is the most expensive option, and it has limited colour and style options. It can also be noisy during rainfall or when walked on.

In conclusion, the best material for your deck boards depends on your specific needs and preferences. Consider factors such as budget, desired appearance, maintenance requirements, and environmental impact when making your decision.

Spacing Between Joists

If you are using composite decking, the manufacturer's installation instructions will specify the required joist spacing, which is typically a maximum of 16 inches on centre. For diagonal board placement, a maximum of 12 inches on centre is recommended. If you are installing deck boards at a 45-degree angle to your joists, you will need to reduce the joist spacing to 12 inches on centre.

Local building codes may also dictate the required joist spacing, so it is important to check with your city's building department to ensure your deck complies with any local or state requirements.

To ensure your deck is safe and structurally sound, it is crucial to plan your joist spans and spacing correctly and to comply with building codes.

Safety Considerations

When working with deck screws, there are several safety considerations to keep in mind. Here are some detailed guidelines to ensure a safe and secure process:

Material and Coating Selection:

• Opt for corrosion-resistant screws, especially if you're working with pressure-treated lumber. Galvanized screws with a zinc coating or stainless steel screws offer excellent protection against corrosion.
• Stainless steel screws are ideal for areas with high moisture or exposure to salt. They provide superior resistance compared to galvanized screws.
• Choose screws with specific coatings like polymer or epoxy designed for chemically treated lumber. These coatings ensure the screws maintain their strength over time.

Screw Length and Diameter:

• Select the appropriate screw length and diameter to match the deck board thickness.
• Ensure the screws penetrate the joists by at least 1 inch. For heavier boards, consider using screws with a wider diameter to increase grip and strength.
• Refer to the wood dimensions and match them with the screw specifications for a secure and stable fit.

Pre-drilling and Driving Techniques:

• Pre-drilling holes for deck screws is crucial to prevent wood splitting, especially with pressure-treated lumber due to its density and chemical treatment.
• When pre-drilling, ensure the holes are slightly smaller than the screw diameter for the best grip.
• Drive screws straight to avoid an angle that could cause splitting.
• Use a drill with adjustable torque to control the driving depth and avoid overtightening. Snug screws are ideal, not forced.

Safety Gear:

• Always wear appropriate safety gear when working with deck screws and power tools. This includes gloves and protective goggles to safeguard your hands and eyes.
• Ensure the work area is clear of any debris, rocks, or vegetation that could cause tripping hazards or interfere with the installation process.

Building Codes and Compliance:

• Familiarize yourself with local building codes and regulations regarding deck construction. These codes outline the approved screws, corrosion resistance requirements, and specific screw sizes for certain projects.
• Check if your project requires building permits and schedule inspections at various stages of construction, including footing, framing, and final inspections, to ensure compliance and safety.

By following these safety considerations, you can ensure a secure and compliant deck construction process while minimizing the risk of accidents and potential hazards.

Aesthetic Considerations

When choosing the right screw size for your deck, aesthetics are an important consideration. The screws you choose will be visible unless you opt for hidden fasteners, so it's worth thinking about the colour and finish.

The colour and finish of screws can vary, and some are designed to blend in with specific decking materials. For instance, if you're using cedar or composite decking, coated screws may leave a residue or cause discolouration over time. In this case, stainless steel screws are a better option, as they are not coated and will not stain the wood.

If you want a clean, seamless look for your deck, you might consider using hidden deck screws. These are concealed from view, providing a smooth surface without visible screw heads. One example is the CAMO system, which uses a handheld jig that fits over the width of the deck board. The screws are then drilled diagonally through the sides of the board into the joist, keeping them out of sight.

Another option for a sleek, modern look is to use clip fasteners or similar systems, which secure the boards without the need for visible screws. These fasteners are often used with grooved deck boards and less intrusive screw types, such as trim head or round head screws, to help hide the connection points.

In summary, when choosing deck screws, consider the colour, finish, and type of fastener that will best suit the aesthetic you wish to achieve. Whether you're aiming for a natural wood look or a sleek, contemporary design, there are screw options available to enhance the visual appeal of your deck.

Frequently asked questions